AgCenter scientist monitors mosquito resistance to insecticide

Baton Rouge, La. — An LSU AgCenter entomologist is working with mosquito control employees in Louisiana to help them learn how to evaluate insecticide resistance in their regions.

Johnny Morgan

While many programs in the state already evaluate insecticide resistance regularly in those mosquitoes that are vectors of West Nile virus, AgCenter entomologists are including potential vectors of Zika virus to this list of species to evaluate.

“In 2016, there were three parishes in the state that we incorporated into a pilot program to enhance their mosquito control programs’ ability to evaluate for insecticide resistance. These parishes included Cameron, Ouachita and DeSoto,” said AgCenter entomologist Kristen Healy. “In 2017, we received funding to help create more of a statewide program.”

In 2017, Healy received $260,000 from the U.S. Centers for Disease Control and Prevention to support two programs for better understanding potential vectors of Zika virus.

The first project helps mosquito control programs evaluate insecticide resistance in species of mosquitoes that lay eggs in containers. These are ones that often are most capable of transmitting certain viruses, such as Zika or chikungunya, she said.

The other project evaluates the statewide distribution of these container species to better assess risk of potential virus transmission.

“The study is just beginning, so right now we are collecting eggs from numerous volunteers from around the state and storing them until we have all the equipment needed to conduct the tests,” Healy said. “We received the funding in July and are winding down our egg collecting right now. We’ll be working through the fall determining the species collected.”

Once her tests are finished, Healy will be able to see where different species live in the state. This will help determine where the greatest risks of certain mosquito-borne viruses could be transmitted if they are ever present in the state.

Zika was first detected in the African country of Uganda, then in Asia, then in the Caribbean, but it has yet to show up in Louisiana, Healy said.

“While we have had several people coming into Louisiana with the virus, to date, there has been no local transmission in the state,” she said.

The two main species that are suspected as vectors of the disease are the Asian tiger mosquito and the yellow fever mosquito. These species lay eggs in backyard containers, such as buckets, trash cans, discarded tires, bird baths or anything that can hold water for seven days or more, she said.

The best thing people can do is always prevent and protect themselves from mosquito bites. Choose EPA-registered repellents and apply according to label instructions. Limit outdoor activity when and where mosquitoes are most active. Repair window and door screens to prevent entry of mosquitoes indoors. And limit standing water in your backyard.